The use of natural products in colorectal cancer drug discovery.

INTRODUCTION: Natural products (NPs) are evolutionarily designed and contain more complex and challenging structures than synthetic compounds. Since the 1980s, the pharmaceutical industry has gradually shifted to a strategy of developing targeted agents by screening libraries of synthetic compounds. However, NPs have recently received renewed focus as a rich repository for drug discovery. Irinotecan was developed as a derivative of camptothecin and was applied in standard regimens for metastatic colorectal cancer (CRC) worldwide. Additionally, polysaccharide K is approved for CRC in Japan and Taiwan in combination with cytotoxic agents. However, after the approval of irinotecan in 1996, no anti-cancer agents derived from NPs have been approved for CRC. AREAS COVERED: This review discusses NPs that are currently under investigation for the treatment of CRC. In addition, other NPs derived as purified ingredients and crude extracts are listed and also discussed. EXPERT OPINION: The use of NPs for the discovery of anti-cancer agents has not been fully investigated. New technologies that are currently applied for synthetic compounds may be utilized for anti-cancer drug discovery including NPs for CRC.

[A case of early cystic duct carcinoma concomitant with xanthogranulomatous cholecystitis (XGC)].

We reported a case of early cystic duct carcinoma concomitant with xanthogranulomatous cholecystitis (XGC). This case was a 72-year-old man in whom thickening of the gallbladder wall was pointed out an abdominal ultrasonography and elevation of the CA19-9 level was detected at a local clinic. Endoscopic ultrasonography and CT demonstrated a mass in the cystic duct. Mapping biopsy using peroral cholangioscopy (POCS) revealed a diagnosis of cystic carcinoma with superficial flat growth, therefore a pylorus-preserving pancreatoduodenectomy was performed. Histopathological diagnosis was well differentiated papillotubular adenocarcinoma with superficial flat spread and the thickening of the gallbladder wall was XGC. A case of early cystic duct carcinoma concomitant with XGC is extremely rare.

[Regression of MALT lymphoma of the rectum after Helicobacter pylori eradication therapy in a patient negative for Helicobacter pylori].

A 53-year-old woman was referred to our hospital for further examination of a rectal polypoid lesion. Colonoscopy revealed a submucosal tumor in the rectum (Ra) and a diagnosis of MALT lymphoma was made on the histological examination of the biopsy specimens and Southern blot analysis of the immunoglobulin heavy chain gene rearrangement. Although the patient was negative for Helicobacter pylori, H. pylori eradication therapy was performed. Colonoscopy 3 months after the eradication therapy showed disappearance of the rectal tumor. H. pylori eradication appears to be a useful treatment for not only H. pylori-positive colonic MALT lymphoma but H. pylori-negative colonic MALT lymphoma.

[A case of primary gastric mantle cell lymphoma].

Endoscopic examination of a 60-year-old man revealed multiple erosions in the gastric antrum. After 6 months, erosions also formed in the duodenal bulb and systemic lymph nodes become enlarged. After 20 months, the gastroduodenal erosions developed into mucosal ulcers, and the systemic lymph node swelling progressed. Histological examination of the neck lymph node showed mantle cell lymphoma (MCL). This result agreed with the results of the gastroduodenal biopsy. This case was diagnosed as recurrent primary gastric MCL in other areas, with systemic lymph node metastasis and bone marrow invasion. Hyper-CVAD (cyclophosphamide, doxorubicin, vincristine, and dexamethasone), high-dose methotrexate and cytarabine in combination with Rituximab and stem cell transplantation was performed. The gastroduodenal lesions and atypical cells in the bone marrow disappeared after 2 cycles of the chemotherapy. Metastatic lymph node swelling regressed after stem cell transplantation. We have had no evidence of recurrence for 50 months. Primary gastric MCL is very rare and cyclin D1 immunohistochemistry and FISH assay were very useful for the diagnosis of MCL.

[A case of pancreatic endocrine tumor developing from intraductal papillary mucinous neoplasm (IPMN)].

In March, 2004, a 64-year-old man was given a diagnosis of IPMN of the pancreas in postoperative CT of left shoulder blade chondrosarcoma. In October, 2007, because a tumor in the pancreas body was found, distal pancreatectomy was performed a diagnosis of the poorly differentiated adenocarcinoma. Histopathologic diagnosis revealed as pancreatic endocrine tumor and immunity dyeing was useful for differential diagnosis. A case of pancreatic endocrine tumor developing from IPMN has a possibility not rare for frequency, but few reports are available so far.

Solid cystic tumor of the pancreas: report of six cases and a review of the Japanese literature.

Although many cases of solid cystic tumor of the pancreas (SCT) have been reported, its nature and histogenesis remain controversial. We herein report six cases of SCT, including three cases of noncystic type. A review of 22 cases of noncystic type SCT, including our 3 cases, was carried out to compare their features with those of 173 cases of classic SCT reported in Japan. Noncystic type SCTs tend to occur in male patients and are smaller in size and less frequently symptomatic, although they show histological characteristics similar to those of classic SCTs. The developmental process might be a cause of cyst formation. The accumulation and analysis of many, at present, "atypical" cases for clarification of its nature, will, it is hoped, lead to a new nomenclature for this condition that adequately describes its biological origin.